Now it's been more than a week since the Arizona couple went missing, and investigators say they suspect foul play. Their dark gray 2008 Honda Accord was found abandoned, but still, family members say there's no trace of them.
"Our priority is to locate this missing couple, yet we have evidence that suggests foul play," Pinal County Sheriff Paul Babeu said in a statement. "This is not just a search, but it is also criminal investigation into the couple's disappearance. We shall continue our search and investigation simultaneously."
Babeu didn't provide additional details on why detectives suspect criminal activity.
"We have no further details at this time, we are looking to provide the family and our community with answers," he said, "yet we are restricted due to the nature of this investigation."
Michael Careccia's son first reported them missing in a 911 call on June 22, telling a dispatcher his 44-year-old father and 42-year-old stepmother hadn't been seen all day after leaving their home near Maricopa to head to work.
"I'm worried about him and ... their phones are off," he says in a recording released by authorities. "They've been gone for 12 hours now."
Since then, volunteers have been searching the desert, investigators have gone door-to-door with fliers and there are rewards for information that will help solve the case.
The Pinal County Sheriff's Office said in a Facebook post
that it had "searched with air, ground and K9 resources soon after the report was filed, but found no signs that the couple is lost in the desert."
"We are happy that it's shifted from a missing person's case to a criminal investigation. Bottom line is let's get some answers and find out what happened to get them home," said Geoff Dugan, the brother-in-law of Michael Careccia
On a Facebook page dedicated to a search for the missing couple, posts describe their disappearance as "unexplainable."
"It's certainly unusual for a couple to just go missing. People don't just disappear, there's usually more to it," Pinal County Sheriff's spokesman Mark Clark told CNN. "But we are not going to stop the investigation until we find out what happened to them."
The Sheriff's Office said it was serving a search warrant on a property near the couple's home. A person of interest has been detained in connection to the disappearance, authorities said.